Although relatively new, two dimensional electrophoresis has proven to be a powerful technique for separating and identifying proteins in complex mixtures, the availability of suitable gradient gels limits the utility of this technique and involves considerable time consuming handwork. An additional problems stems from the lack of adequate separation of low molecular weight compounds (less than 10,000 Daltons). It would be desirable to produce a high capacity pre-cast gradient gel system that permits analysis of important proteins and peptides below 10,000 Daltons. POROPLASTIC gels are well suited to this and would offer the following advantages: 1. Lower molecular weight range 2. Uniformity and reproducibility 3. Ease of manufacture 4. Potentially better resolution/separation 5. Ease of varying solvent During the Phase I program, three different techniques for production of Poroplastic gradient gels will be investigated. The Poroplastic gradient gel membranes produced will be compared to commercially available polyacrylamide gradient gels in their ability to separate various protein mixtures with particular emphasis on the (less than 10,000 Daltons) range.